Nine new chromane-type meroterpenoids,
including the rare nor-meroterpenoid
sargasilol A (1) and the eight meroditerpenoids sargasilols
B–I (2–9), were isolated from
a China Sea collection of the brown alga Sargassum siliquastrum, together with six known analogues (10–15). The structures of the new chromanes were identified by
extensive spectroscopic analysis and by comparison with previously
reported data. Compounds 1–3 and 6–15 exhibited inhibition against LPS-induced
NO production in BV-2 microglial cells, and 1, with a
shorter carbon chain, was the most active one. Compound 1 was established as an anti-neuroinflammatory agent through targeting
the IKK/IκB/NF-κB signaling pathway. As such, the chromanes
from brown algae could provide promising anti-neuroinflammatory lead
compounds for further structural modification.